1. Field of Invention
The present invention generally relates to a driver circuit and a method for operating such a driver circuit.
2. Description of Related Art
Driver circuits are used in diverse ways in integrated digital circuitry, for example as drivers for lines, busses of integrated circuits or the like.
In recent years, the requirements imposed on electronic components and thus also on the driver circuits, in particular in electronic systems clocked at high speed, have risen rapidly. One of these requirements that have risen relates for example to electromagnetic compatibility (EMC).
Integrated digital circuits are generally connected via conductive connections to peripheral devices, power sources and the like. This results, inter alia, in parasitic capacitances which lead to disadvantageous signal alterations. External loads, the parasitic capacitances and also the driver transistors themselves form an electronic network in which resonance effects, reflections and the like can occur. These generate transient signals which can deviate from their envisaged magnitude and shape and exceed or fall below their final voltage states. On account of the densely packed design on chips, such transient signals can adversely affect not only their own signal lines themselves but also signal lines of adjacent electronic components.
On account of the increasing requirements, there is a need to improve electronic components, corresponding driver circuits and the like, in such a way that these disadvantages can be avoided.
U.S. Pat. No. 5,537,067 describes, for example, a driver circuit which can be operated in order to regulate the rise times and fall times of signals supplied to a load. This driver circuit has a first inverter with a PMOS transistor and an NMOS transistor and a resistor. A second inverter has a PMOS transistor and an NMOS transistor. The resistor and additionally provided capacitors increase the transition times of the output driver signal in order to control the electromagnetic radiation caused by short transition times of the output signal.